Bulldozer



3 Sheets-Sheet 1 INVENTOR ATTQRNEY K, il mv e f HQVQAQEE QQ @i G. S. ALLIN Aug. 2, 1938.

BULLDOZER Filed NOV. 25, 1953 G. S. ALLIN Aug. 2, 1938.

3 Sheets-Sheet 2 Filed NOV. 25, 1933 G. S. ALLIN BULLDOZER Aug. 2, 1938.

3 Sheets-Sheet 3 Filed Nov. 25, 19:20

INVENTOR GEQSHLL//v BY QW. D v

ATTORNEY rammed Aug. 2, 1938 PATENT OFFICE BULLDOZER George- S. Allin, Seattle, Wash., assignor, by

mesne assignments, to Gar Wood Industries, Inc., Detroit, Mich., a corporation of Michigan REISSUED Application November Z5, 1933, Serial No. 699,759

7 Claims.

This invention relates to improvements in earth moving machines and it has reference more particularly to motorized machines of that'character now generally known in trade as Bulldozers and"Roadbuilders, and which are extensively used in road building, grading, excavating and other earth moving operation. Such machines,

in their general arrangement, employ a tractor for the motive power and this is usually of the crawler type. Forwardly of the tractor a blade is mounted for the grading or moving of dirt and this is suspended from the tractor frame for adjustment to diierent depths and for casting the dirt to either side of the roadway.

Heretofore it has been customary to support the blade at its diierent positions of adjustment by means of lifting devices mounted partly on the main frame of the tractor and to actuate it by various arrangements of links and levers to whichpower was manually applied, or applied by geared connections with the tractor drive shaft. However, the suspending of the lifting devices from the main frame of the tractor has the disadvantage of placing considerable strain on the front spring supports connecting the main frame with the track frames and furthermore, adjustment of the blade while the vehicle was in motion has been diiicult.

It is the principal object of the present invention to improve upon the construction of machines of this character as heretofore used, particularly in the means for and manner of suspending the blade so that it may be more easily and more positively adjusted. to various positions' and Also, which may be operated to change the setting of the blade while the tractor is in operation.

Another object of the invention resides in the details of construction of the mechanical devices for rigidly and securely supporting the blade and its adjusting means from the track frames of the tractor in a manner whereby forces applied through the blade and its supports will be absorbed directly by the tracks and not` applied to the tractor frame.

Other objects of the invention reside in the details 'of construction of the various parts, in their relationship and mode of operation, as will hereinafter be more fully described. l

In accomplishing these and other objects of th invention I have provided the improved details of construction, the preferred forms of which are illustrated in the accompanying drawings, wherein- Fig. 1 is a side elevation of a machine embodying the present invention.

Fig. 2 is a partial rear elevation showing the pump, valve and storage tank used in connection with the hydraulic cylinders.

Fig. 3 is a plan View of the machine.

Fig. 4 is a front elevation of the same.

Fig. 5 is a transverse section, substantially on li'ne 5 5 in Fig. 1.

Fig. 6 is a side view, partly broken away for better illustration, of a rocker arm used in the blade adjusting means.

Referring more in detail to the drawings- In its present embodiment-the machine utilizes a tractor of the crawler, or self laying track type, as seen best in Fig. 1. The tractor. is designated in its entirety by reference numeral I and it includes theusual main frame structure, or chassis v2 which mounts the engine designated at v3. At opposite sides of the main frame are the track mounting frames 4-4. -At the forward ends of the frames 4-4 are track mounting wheels 5 and at their rearward ends are the track driving wheels 6. 'I'he traction belts or tracks 'I-l are extended about the wheels 5 and 6 and between these wheels the upper runs of the tracks are supported by idler rollers B and the lower run is guided and held in contact with the ground by idling rollers 9; the rollers 8 and 9 being supported from the track frames'4-4 as is the usual practice. v

In this construction, the belt driving wheels 6 6 are driven by means of the differential shafts In-Ill, which, as seen in Fig. 3, are driven from the engine shaft I I through suitable transmission gearing I2.

The two track frames 4-4 are arranged symmetrically at opposite sides of the main frame O f the tractor and near their rearward ends are rotatably mounted upon the opposite ends of a shaft I 5 which is xed in and extends transversely through the main frame of the tractor as a support for the latter. 'I'he forward end of thetractor 4would be supported from the track i'rames through the mediacy of springs, not shown, to permit of a relative upward or downward movement of the tracks incident to travel over` uneven surfaces.

The earthy moving 'blade I 8 is mounted forwardly-.of the tractor by means of a yoke like supporting frame comprising opposite side beams 20--20 'extending yalong opposite sides of the tractor and rigidly connected across their forward ends by a cross bar 2| of a forwardly pointed V li-ke form. At their rearward ends the Side beams 20-20 vhave brackets 23 flexed thereyto and these are formed with bearings which are rotatably fitted to the opposite end portions |5a of the cross shaft l5. Nuts 25 are 4threaded onto the ends of the shaft to hold the parts properly assembled. `rl"his manner of mounting the blade supporting frame permits the forward end to be raised or lowered thereby tovadjust the elevation f the blade i8.

The ground working blade |8 is preferably straightfrom end to end and is of such length that its ends terminate. outside the longitudinal llines of the outside of the tracks. At the back side of the blade, midway between, its ends, are

' vertically spaced flanges 28-28 which mount a vertical` pin 21 extending' pivotally through a swivel head 28. This head is 'provided with a horieontalshank 29 xedly mounted in a bearing 30 vhired centrally in the cross beam 2| of the lblade supporting frame. The connection provides for adjusting the blade to chierent :an-

guiar positions across the line of travel of the tractor. j

Slidably overlying the opposite side beams 20,-'28 of the blademounting frame are brace struts 32-32 for the blade. These struts are connected at their forward ends to the opposite ends of the'blade through the mediacy of knuckles 33. These are pivotally attached to the beam ends by vertical pivot pins 34 and are likewise ,attached to flanges 35 on the back side of the blade by horizontal pivot pins 36.- Attheir rearward ends the brace beams 32-32 are rigidly secured to the side beams 2li-20 of the blade mounting frame by means of vertical pivot pins 31 extended through registering holes in the parts. Angular adjustment of the blade is permit-ted by withdrawing the pins 31 and there are holes 38 provided in spaced -relation along the coacting beams 4`to receive the pins for the different positions of adjustment of the blade.

The side beams'of the blade supporting frame preferably are of channel iron, facing inwardly, and the struts 32 likewise areof channel iron and telesccpically fitted over-the frame beams.

Thus, the flanges of the struts 32 ,engage thefram'e beams to prevent upward or downward tilting of the forward ends of the struts relative to the frame. This construction is thus rendered rigid and substantial, yet easily and readily adjustable.

' The novelty of the present invention resides particularly in the means for quickly adjusting the blade to different-elevations and for holding it at the different positions of adjustment.

the track belt therethrough and each pair .of

yokes supports the opposite ends of a pair of parallel, truss-like bars 45 above the track and longitudinally thereof; there being pins 44 extended through the upper ends of the yoke arms and through thefends of the truss bars to support the latter.

Y Disposed between the truss bars 45 at oppo,

site sides of thetractor are rocker levers 46-46 Divctally supported by pivot bolts @l1 extended therethrough and through the apex portions of paired trusses.

Each leverl extends lengthwise of the track and has a relatively long forward arm 46a overlying the side beam 20 of the blade mounting frame at that side of the tractor. Bolts 48 connect the forward ends of these lever'arms 46a with the forward portion of the blade mounting frame. The bolts 48 are attached at their lower ends by pivot pin 49 to flanges on the frame bar 2| and at their upper ends extend loosely through vertical openings 53 at the forward ends of the levers and have nuts threaded onto their upper ends to complete the connection. Colled springs 52 are placed loosely about the bolts 48 to bear at their opposite ends against the frame members and lever arms to yieldingly resist upward movement of the frame and to act as shock absorbing means for the frame.

. Movement of the rocker arms 46 for raising or lowering the blade frame is under control oflhydraullc means as will now be described. Associated with each lever are paired hydraulic cylinders 60-E|; each of which comprises a series of telescopic cylindrical sections, as seen best in Fig. 5. The lower sections of the paired cylinders are pivotally mounted by the cross bolts 44 whichsupportv the opposite ends of the truss bars. The

upper end section-of the cylinder 6i! at each side is pivotally attached by a pin 64 to the lever arm ata point forwardly of its supporting pin 41. Likewise the upper section of cylinder 6| at each side is pivotally attached by a pivot pin 66 to the rearward end of the lever which, as seen in Fig. 1, is relatively short and is upwardly directed. The arrangement provides that if the rearward cylinders are extended by an application of pressure medium4 theretol the forward ends of the lever arms will be actuated downwardly and the blade supporting frame will be lowered accordingly. Also, if the forward cylinders are extended', the arms will be 'lifted and the blade raised accordingly.

Actuation of the hydraulic cylinders for raising or lowering the blade is effected by applicationof a. liquid pressure medium to one set of cylinders while relieving pressure from within the other cylinders. As seen in Figs; 2 and 3, there is a hydraulic punip l5 operatively con'- nected to be driven by the engine shaft, and this pump has its inlet side connected by a hose 1,6 with a tank 11 containing a supply of liquid such as oil. The discharge side of the pump is connected by a hose 1li with a valve housing l. The housing 19 has a hose -connection 80' with a `header 6| from which hoses 82--82 lead respectively, to the forward cylinders 60; and also it has a hose connection 83 leading to a header 84 from which hose connections 85-85 lead to the rearward cylinders 6|. -A valve plug 86 is movable in the valve housing by means of a lever 81- to provide for forcible application bythe pump of pressure medium to either the forward or rearward cylinders while draining the others into the tank. A neutral positiqn or the valve closes all the cylinders to inlet or outlet of liquid and this retains the levers at set positions.

A feature of this construction is in the proviapplied through the blade is received by the 'claim as new therein and desire to secure by Letters Patent is- 1. In combination, a tractor having a main frame, track frames at opposite sides thereof, a cross shaft fixed in the main frame and pivotally mounting the track frames, a blade mounting frame pivotally mounted on-the ends of the cross shaft and extending about the forward end of the tractor, a blade mounted by the latter frame across the front of the tractor, lever arms pivotally mounted on the track frames with ends operatively connected with the blade frame, and means secured on the track frames for adjusting the positions of the levers to raise or lower the blade frame and for holding said levers at set positions of adjustment.

2. In combination, a tractor having a main frame, relatively movable track frames at opposite sides thereof, means for mounting a blade forwardly of the tractorfor vertical adjustment,

lever arms pivotally mounted on the track frames, withmovable ends operatively connected with the blade mounting means for adjusting and retaining the latter at different positions of vertical adjustment and hydraulic means on the track frames for adjusting the lever arms and for holding them rigid relative to the track frames.

3. In combination, a tractor having a main frame and relatively movable track frames at opposite sides, a frame mounting a blade forwardly of the tractor-for vertical adjustment, pivotally supported rocker levers on the track frames, means connecting the levers with the blade mounting frame for adjusting it vertically, hydraulic cylinders on the track frames operatively connected to the rocker levers and means for selectively applying a pressure medium to said cylinders to actuate the levers together in opposite directions.

4. In combination, a tractor comprising a main frame, track frames at opposite sides thereof, a blade mounting frame on the tractor and extending forwardly thereof, a bladevmounted by the latter frame,` a rocker lever pivotally mounted on each track frame, means connecting the forward ends of said levers with the blade frame, a pair of hydraulic cylinders mounted on each track frame and connected with the corresponding rocker lever at opposite sides of its pivot point and means operable for selectively applying a pressure medium tothe cylinders to actuate the lever arms for .vertically adjusting the blade mounting frame and for closing said cyl- I inders to retain the pressure medium to hold the blade frame at different positions of adjustment. 5. In combination, a tractor having a main frame, a cross shaft mounted in the main frame,

track frames pivotally mounted on the ends of the cross shaft at opposite sides of the main frame, a blade mounting frame extended across the forward end and along the sides of the tractor and pivotally mounted on the ends of the cross shaft, a blade mounted by the said frame across the forward end of the tractor, a rocker lever pivotally supported upon each track frame, a link operatively connecting the forward end of each lever with the forward end 'of the blade frame, a pair of hydraulic cylinders mounted on each track frame and operatively connected with the corresponding lever arm at opposite sides of the pivot, a hydraulic pump, pipes connecting each cylinder with its corresponding cylinder at the opposite side of the tractor, and a valve mechanism connected with the pump and adjustable to positions for a selective application of hydraulicl pressure medium to either set of cylinders while relieving pressure from the other set and adjustable to a neutral position to retain any adjustment of the levers.

6. In a road working machine, a main-frame, track frames pivotally connected thereto, a scraper frame pivotally connected to said track frames, a pair of supports extending upwardly from each ofsaid track frames, a b'ell crank arm pivotally f mounted on each pair of supports, means interconnecting one end of each of 'said bell crank arms and said scraper frame, and actuating mechanism mounted on one support of each pair, said actuating mechanisms each being connected to one end of its respective bell crank arm and effective to tilt said arm to raise and lower said scraper frame.

7. In a road working machine, a main frame, a track frame connected thereto, a scraper frame pivotally mounted on said track frame, a pair of supports extending upwardly from said track frame, a member rigidly interconnected to said supports, a lever pivotally connected to said member and having one end connected to said scraper frame and hydraulic means interconnecting said lever with each of said supports for tilting said lever whereby to vary the vertical position of said scraper frame.

. GEORGE S. ALLIN. 

